Guide
Water filtration and RO system installation as a plumbing revenue line
Published
Whole-house water filtration and under-sink reverse osmosis installation is a high-margin add-on that every plumbing shop should be selling on every water heater and repipe job. A typical residential install runs $1,500–$6,000 (verified April 2026 via Angi, Fixr, and contractor operator data), with gross margins between 45% and 65% when the shop controls equipment sourcing. The sales motion is short, the install is fast, and the customer often requests ongoing filter change service — which creates a recurring annual revenue tail worth more than the initial ticket over a 10-year horizon. This is exactly the kind of service line that moves a plumbing shop from reactive emergency work to planned, appointment-based revenue.
Why filtration belongs in every plumbing shop's price book
The water quality market is growing fast. According to market research firm Grand View Research (verified April 2026), the US residential water treatment market surpassed $5 billion in 2025 and is projected to grow 7–9% annually through 2030. That growth is being absorbed primarily by direct-to-consumer brands (Aquasana, Culligan, RainSoft) and big-box installers, not by plumbing shops. Every plumber competing on water heater replacement is already losing the filtration attach sale to a Home Depot flyer and an online brand.
Bringing the category in-house delivers:
- Ticket size increase on existing customers
- Strong margin (equipment sourced through wholesale beats retail by 40%)
- Recurring filter replacement revenue
- Natural pairing with softener, tankless, and whole-home repipe work
- Differentiation from competitors who only quote the mechanical work
Product categories and typical installed pricing (verified April 2026)
Filtration is not one product — it is four or five distinct categories, each with a different price point and install scope.
| Category | Typical installed price | Typical tech time |
|---|---|---|
| Under-sink carbon filter (single stage) | $285–$485 | 45 min |
| Under-sink 3-stage filter | $485–$785 | 75 min |
| Under-sink reverse osmosis (4-stage) | $785–$1,450 | 90 min |
| Under-sink RO with permeate pump or tankless RO | $1,250–$2,200 | 2 hours |
| Whole-house carbon filter (sediment + carbon) | $1,500–$2,800 | 2.5–4 hours |
| Whole-house carbon + UV sterilization | $2,400–$4,200 | 4–5 hours |
| Whole-house multi-stage (sediment + carbon + specialty) | $3,200–$5,500 | 5–7 hours |
| Whole-house filtration + softener combo | $4,500–$7,800 | 6–9 hours |
| Commercial / light industrial RO system | $6,500–$18,000+ | Project scope |
Source: aggregated Angi, Fixr, and HomeAdvisor April 2026 pricing pulls, plus contractor operator data from plumbing group surveys.
Where the margin lives
A typical whole-house carbon filter install priced at $2,400:
| Line item | Cost |
|---|---|
| Equipment (wholesale, single filter unit with bypass) | $425–$685 |
| Pre-filter, fittings, tubing, shutoffs | $85–$145 |
| Labor: 1 tech × 3.5 hours loaded | $205 |
| Truck and overhead | $130 |
| Direct cost | $845–$1,165 |
| Gross margin at $2,400 sell | $1,235–$1,555 (51–65%) |
The margin is meaningfully better than on standard plumbing service work. The reason: equipment sourcing. A shop buying filtration gear through a wholesale plumbing supplier or direct from manufacturers like Springwell, Aquasure, or commercial lines from Watts or Pentair pays 40–55% of retail. A homeowner buying the same unit online or from Home Depot pays full MSRP plus shipping. The labor is the same either way; the shop captures the equipment margin.
Under-sink RO: the easiest attach
The under-sink RO install is the single highest-ROI add-on to any kitchen plumbing job. A customer replacing a kitchen faucet ($285 job) who agrees to add a 4-stage RO system walks out with a $1,100–$1,600 ticket. The install adds 75–90 minutes of tech time to a visit that is already underway.
Standard RO system stages:
- Sediment pre-filter
- Granular activated carbon
- RO membrane (semi-permeable, rejects dissolved solids)
- Post-carbon polish before delivery to dedicated faucet
Modern systems add remineralization, UV sterilization, or alkaline boost as 5th/6th stage options at $200–$450 upsell each.
Filter replacement schedule (this is where the recurring revenue lives):
| Filter stage | Replacement interval | Customer cost |
|---|---|---|
| Sediment | 6–12 months | $35–$65 |
| Carbon | 12 months | $45–$85 |
| RO membrane | 24–36 months | $85–$165 |
| Post-carbon | 12 months | $35–$65 |
| Tech labor (annual visit) | Annual | $125–$185 |
A shop that bundles annual filter service at $185–$285/year builds an ever-growing service base. After 5 years of installs, a typical shop carries 150–400 active filter-service customers generating $35k–$100k annually with negligible acquisition cost.
Whole-house filtration: the premium sell
Whole-house systems treat every fixture in the home. The sales pitch lands strongest in three customer profiles:
- Municipal water complaints — chlorine taste, smell, or color concerns
- Well water — iron, sulfur, hardness issues
- Health-conscious buyers — remodels, new home purchases, young families
The install is 4–7 hours depending on where the main enters the house, whether the customer wants a bypass loop for outdoor spigots, and whether it is combined with a softener (most common pairing — see the water softener installation business guide).
Most shops make the most money on the combo install: whole-house filter + softener in one visit, one bid, one tech crew. A $6,500 combined install at 55% margin is $3,575 gross margin in a single day.
The sales approach that actually works
Filtration does not sell from a truck flyer. It sells from a conversation during a water-adjacent service call. Effective approach:
- Lead with a water test. A $15 TDS meter and a chlorine test strip take 2 minutes and produce the customer's actual numbers. That number is the sales tool.
- Connect to a problem the customer already mentioned. Hard-water scale, bad-tasting tap water, skin dryness, damage to fixtures. Filtration addresses all of these.
- Present it as a system, not a product. A price tag on a filter vessel means nothing. A "clean water solution for your whole home" is a different sale.
- Offer financing on the premium installs. A $5,500 install at $95/month is easier to close than a lump sum. See the consumer financing for contractors 2026 guide.
Shops that add a simple water test to every water heater, softener, and repipe visit convert 15–25% of customers to a filtration sale. That is a 15–25% increase in close rate on a line that adds zero customer acquisition cost.
Common install and sales mistakes
- Not explaining the difference between RO and filtration. Customers often use the terms interchangeably. RO removes dissolved solids (mineral content); carbon filtration does not. Wrong product for the wrong problem creates churn.
- Under-sizing whole-house flow. A 10-GPM filter in a home with 15-GPM demand creates pressure drop and customer complaints. Size to peak flow plus margin.
- Not offering the service agreement at install. Selling the filter once and never seeing the customer again is leaving 2–4x the install revenue on the table over the filter lifespan.
- Recommending products the shop does not stock. A filter sale that requires ordering a part nobody has stalls the install by a week and often kills the deal.
- Pricing only by equipment MSRP. The job is labor + equipment + margin. A retail-equivalent price tag kills the premium that makes the line profitable.
Software that handles filtration service
The ongoing filter replacement service needs recurring scheduling, inventory tied to specific customer systems (so the tech shows up with the right filter), and annual reminders.
- ServiceTitan — strong recurring service programs, inventory at customer-location level.
- Housecall Pro — clean for small shops; recurring job templates work well.
- Jobber — good for scheduling annual visits and customer tagging.
- Workiz — plumbing-friendly dispatch if filter service is a small share of overall work.
The plumbing software buyer's guide has the full sizing framework.
Realistic revenue contribution
A plumbing shop adding filtration as a named line typically sees:
- 3–8 filtration/RO installs per month after 6 months of attach-selling
- Average ticket $2,200 at 55% gross margin
- Monthly filtration install revenue: $6,600–$17,600
- Recurring service revenue (growing every quarter): $400–$6,000/month building to $3k–$8k/month by year 3
- Combined annual contribution: $85k–$275k by year 2, $150k–$425k by year 4
Filtration is the clearest example of a plumbing service line where the long-term recurring revenue eventually exceeds the initial install revenue — the opposite of most plumbing work. See context in the plumbing service pricing guide.
Related: water softener installation business, water heater replacement business, tankless water heater installation business, plumbing service pricing guide, plumbing software buyer's guide, consumer financing for contractors 2026.